Boards of this character are made by compacting wood fragments, vegetable fibers, gypsum powder or the like, coated with a suitable adhesive such as glue or a curable resin, in a flat press with application of heat, if necessary. The boards so produced are widely used for structural or decorative purposes, e.g. as facings of floors, ceilings and walls as well as on furniture, with or without ornamental coverings; among their advantages are low manufacturing costs and good soundproofing qualities.
A common property of all such particle boards is their low thermal conductivity. While this may be desirable in some instances, situations do exist where a higher degree of heat conduction would be helpful. This is true, for example, in the case of radiator covers and of facings for ceilings or floors provided with conduits for a heat-carrying fluid designed to control the temperature of a room.
Thus, a space heater or an air conditioner with heat-exchanging conduits or resistance elements covered by such particle boards generally must have a larger capacity or must be operated with more energy than would otherwise be the case, in order to overcome the thermal resistance of its enclosure. Once a thermal equilibrium is reached, however, that excess capacity tends to overheat or overcool the room and is therefore wasted. Another drawback of this low thermal conductivity is the tendency of such boards to deform under thermal stresses due to an uneven temperature distribution.